place strawberries, sugar, fennel pollen (if using) and peppercorns into a glass crock or wide mouth jar. allow to sit for about an hour, then macerate to break up the strawberries. cover and allow to sit 24 hours. (i let mine sit at room temperature, but if you are concerned, it is okay to put in the fridge). after 24 hours macerate the mixture again, aiming to crush the strawberries. you can move onto the next step, or allow to sit another 24 hours at this point. add to the mixture the balsamic vinegar and the cider vinegar and stir well. allow this to sit 7-9 days at room temperature, stirring daily. the sugar should eventually "melt" into the liquid. it is important that you tend to the mixture daily. after 7-9 days. strain the mixture using a fine mesh strainer (if you don't mind a few bits in it) or a strainer with cheesecloth (if you do) and bottle for use. for longer shelf life, i recommend storing in the refrigerator.